Determining the range of signal levels at which an electronic component switches from one state to another in the presence of noise is typically a time consuming task. Current methods for determining this range for electronic components such as comparators often employ pairs of linear searches. One such search begins by running a set of tests at an input signal level for which the results are known to indicate that the component is in a first state for all of the tests of the set and runs successive sets of tests at increased input signal levels until the results indicate that the component is in a second state for a preselected number of the tests in the current set. The other search begins by running a set of tests at an input signal level for which the results are known to indicate that the component is in the second state for all of the tests of the set and runs successive sets of tests at decreased input signal levels until the results indicate that the component is in the first state for a preselected number of the tests in the current set. The searches begin by setting a signal level a short distance away from the expected “comparator trip point” and running a pattern that performs a set of N comparisons in anticipation of obtaining either “all fail” results for one direction of incrimination of the input signal or “all pass” results for the other direction of incrimination of the input signal. If either of these conditions occurs, the signal level is incremented in the appropriate direction and the test pattern is run again for another set of N comparisons. These actions are repeated until one or more of the set of comparisons no longer yields the same result (a “fail” or a “pass”) as at the start of the search.
Linear searches are typically time consuming. The speed of the search can be increased by decreasing the span and/or precision of the search. However, if it is preferred to find the comparator trip region over a reasonably wide range so that the set point accuracy can be quantified and if it is preferred to find the bounds of the comparator trip region precisely so that comparison noise can be quantified, a large number of search steps will typically be required. The situation is compounded if the comparator comprises a number of channels rather than just one.